1

Topic: Scalar request in CASE

Children all greetings!
I read  to dock, section Scalar Subquery Expressions . Here it is written:

Oracle documentation wrote:

A scalar subquery expression is a subquery that returns exactly one column value from one row.
You can use a scalar subquery expression in most syntax that calls for an expression (expr). However, scalar subqueries are not valid expressions in the following places:
....
In WHEN conditions of CASE expressions
....

If I correctly translated, - scalar subqueries cannot be used as conditions in When for CASE expressions.
I try:

--- The first variant
select
case when 1 in (select 1 from dual)
then ' Hello Oracle! ' end
from dual
--- The second variant
select
case when (select 1 from dual) = 1
then ' Hello Oracle! ' end
from dual
--- The third
select
case when 1 in (select 1 from dual)
then (select ' Hello Oracle! ' from dual) end
from dual

All three request successfully fulfilled! - why they fulfilled a question? What not so I translated in dock?

2

Re: Scalar request in CASE

STFF

3

Re: Scalar request in CASE

SQL_boy;
And here it is possible